RCW 47.52.027

The secretary of transportation may adopt design standards, rules, and regulations relating to construction, maintenance, and control of access of the national system of interstate and defense highways within this state as it deems advisable to properly control access thereto, to preserve the traffic-carrying capacity of such highways, and to provide the maximum degree of safety to users thereof. In adopting such standards, rules, and regulations the secretary shall take into account the policies, rules, and regulations of the United States secretary of commerce and the federal highway administration relating to the construction, maintenance, and operation of the system of interstate and defense highways. The standards, rules, and regulations so adopted by the secretary shall constitute the public policy of this state and shall have the force and effect of law.